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74)
74)
The permanent discharge line on a reversing valve is always located:
A)
On the right on the side with three large lines.
B)
On the left on the side with three large lines.
C)
In the middle on the side with three large lines.
D)
By itself opposite the side with three large lines.
Answer:
D
Explanation:
A)
B)
C)
D)
75)
75)
Which of the following is the correct order of the flow in the heating cycle of an air-source heat
pump?
A)
Compressor, reversing valve, indoor coil, outdoor TEV, outdoor coil, reversing valve
B)
Reversing valve, indoor coil, outdoor coil, outdoor TEV, compressor
C)
Compressor, reversing valve, outdoor coil, indoor TEV, indoor coil, reversing valve
D)
Indoor TEV, indoor coil, reversing valve, compressor, reversing valve, outdoor coil
Answer:
A
Explanation:
A)
B)
C)
D)
76)
76)
What kind of check valve would you find in the air conditioner in a 20-year-old-home?
A)
A check valve made of plastic
B)
A check valve that uses a steel ball
C)
A check valve that is inside the metering device
D)
A check valve that has a disk and a spring
Answer:
D
Explanation:
A)
B)
C)
D)
77)
77)
What prevents the refrigerant from flowing through the indoor metering device during the
heating cycle?
A)
The outdoor check valve
B)
The heating shutoff valve
C)
The reversing valve
D)
The indoor check valve
Answer:
D
Explanation:
A)
B)
C)
D)
21
78)
78)
What is the main difference between a heat pump and a fossil fuel furnace?
A)
Heat pumps are easier to install.
B)
Fossil fuel furnaces are hotter.
C)
Fossil fuel furnaces have been around longer.
D)
Heat pumps move heat instead of creating it.
Answer:
D
Explanation:
A)
B)
C)
D)
79)
79)
What component is responsible for reversing the flow of refrigerant in a heat pump?
A)
The reversing valve
B)
The check valves
C)
The compressor
D)
The heating charge compensator
Answer:
A
Explanation:
A)
B)
C)
D)
80)
80)
The reversing valve reverses the direction of refrigerant flow:
A)
And reverses the function of the two heat exchange coils.
B)
By reversing the direction of the compressor motor.
C)
By reversing the airflow through the two heat exchange coils.
D)
By reversing the polarity of the electric power supplying the system.
Answer:
A
Explanation:
A)
B)
C)
D)
81)
81)
The indoor coil is the condenser in:
A)
The cooling cycle.
B)
Both the cooling and defrost cycles.
C)
The heating cycle.
D)
Both the heating and defrost cycles.
Answer:
C
Explanation:
A)
B)
C)
D)
22
82)
82)
Because air-source heat pumps circulate less refrigerant at low ambient temperatures, the
refrigerant not being used is stored:
A)
In the compressor crankcase.
B)
In a suction accumulator or charge compensator.
C)
In a liquid receiver.
D)
In the metering device.
Answer:
B
Explanation:
A)
B)
C)
D)
83)
83)
When are most heat pump reversing valves energized?
A)
During the heating cycle
B)
During all modes of operation
C)
During auxiliary heating mode
D)
During the cooling cycle
Answer:
D
Explanation:
A)
B)
C)
D)
84)
84)
Why are the coils in an air-source heat pump referred to as the outdoor coil and indoor coil
instead of the condenser and evaporator?
A)
Their function (evaporator or condenser) reverses when the unit changes from cooling to
heating.
B)
Because both the coils in a heat pump coils are identical.
C)
It can sometimes be difficult to determine the exact location of the coils.
D)
Refrigerant does not evaporate or condense in a heat pump coil.
Answer:
A
Explanation:
A)
B)
C)
D)
23
85)
85)
Which of the following determines what coil will be the evaporator in the heating or cooling
process?
A)
The coil that has its port covered by the sliding valve
B)
The coil that is connected to the permanent suction
C)
The indoor coil that is always connected
D)
The coil connected to the uncovered port
Answer:
A
Explanation:
A)
B)
C)
D)
86)
86)
A bi-flow thermostatic expansion valve:
A)
Can be used with two different capacity units by selecting the correct flow.
B)
Allows refrigerant flow in both directions.
C)
Can be used with two different refrigerants by selecting the correct flow.
D)
Can be used for creating two stages of heating or cooling.
Answer:
B
Explanation:
A)
B)
C)
D)
87)
87)
The heat sink for an air-source heat pump is:
A)
The air inside the house.
B)
The air outside the house.
C)
The water in the water loop.
D)
Electric strip heat.
Answer:
A
Explanation:
A)
B)
C)
D)
88)
88)
Heat pump A has a SEER rating of 16 and an HSPF rating of 7. Heat pump B has a SEER rating of
14 and an HSPF rating of 9. Which heat pump heats more efficiently?
A)
Heat pump A
B)
Heat pump B
C)
They are about the same heating efficiency by the time both the SEER and HSPF are
considered.
D)
Neither the SEER nor the HSPF can determine which heat pump heats more efficiently.
Answer:
B
Explanation:
A)
B)
C)
D)
24
89)
89)
Why is it important to know what the conditions were when a pump was rated?
A)
It assists in knowing which rating system to use.
B)
Ratings can be skewed based upon test type.
C)
It helps to properly measure the operating costs.
D)
Weather factors can affect the ratings.
Answer:
D
Explanation:
A)
B)
C)
D)
90)
90)
Liquid floodback commonly occurs on air-source heat pumps:
A)
When the heat pump is operated in heating on a warm day.
B)
When the heat pump is operated in cooling with a low charge.
C)
When the defrost cycle is terminated and the cycle reverses.
D)
When the liquid filter drier is stopped up.
Answer:
C
Explanation:
A)
B)
C)
D)
91)
91)
When is the indoor metering device bypassed?
A)
Both the heating and defrost cycles
B)
The cooling cycle
C)
The heating cycle
D)
Both the cooling and defrost cycles
Answer:
C
Explanation:
A)
B)
C)
D)
92)
92)
The heat source for a water-source heat pump is:
A)
The air inside the house.
B)
The air outside the house.
C)
The water in the water loop.
D)
Electric strip heat.
Answer:
C
Explanation:
A)
B)
C)
D)
25
93)
93)
How can a heat pump filter drier be differentiated from a standard filter drier?
A)
By the 600 psig pressure rating
B)
By the directional arrows pointing towards both ends of the drier
C)
By the two copper lines on each end of the drier
D)
By the shiny, polished appearance of the stainless steel core
Answer:
B
Explanation:
A)
B)
C)
D)
94)
94)
Which terminal is responsible for the compressor?
A)
Y terminal
B)
W terminal
C)
O/B terminal
D)
G terminal
Answer:
A
Explanation:
A)
B)
C)
D)
95)
95)
The emergency heat setting on a heat pump thermostat:
A)
Increases the compressor speed to produce more heat.
B)
Operates both the compressor and auxiliary heat to produce the maximum amount of heat
possible.
C)
Energizes the auxiliary heat on first stage and does not turn on the compressor and outdoor
fan.
D)
Notifies the installing contractor that the system needs immediate service.
Answer:
C
Explanation:
A)
B)
C)
D)
96)
The ENERGY STAR® label is awarded to packaged air-to-air units with EERs of ________ or
greater, SEERs of ________ or greater, and HSPFs of ________ or greater.
96)
A)
EER 10, SEER 13, HSPF 7.7
B)
EER 16, SEER 22, HSPF 13
C)
EER 11, SEER 14, HSPF 8
D)
EER 12, SEER 16, HSPF 8
Answer:
D
Explanation:
A)
B)
C)
D)
26
97)
97)
In a dual-fuel heat pump packaged system, when does the furnace go into use?
A)
Once the outdoor temperature drops to the balance point
B)
Once the outdoor temperature is below the balance point
C)
Only when it is most economical
D)
Only during winter conditions
Answer:
A
Explanation:
A)
B)
C)
D)
98)
98)
Which of the following allows air-to-water systems to run more efficiently than air-to-air
systems?
A)
They do not need to be defrosted.
B)
Auxiliary heat is not needed as much.
C)
Supplemental heat is energized all the time.
D)
Cold temperatures are an optimal environment.
Answer:
B
Explanation:
A)
B)
C)
D)
99)
99)
The most common type of demand defrost control:
A)
Senses the compressor current draw.
B)
Operates strictly on time.
C)
Measures the temperature difference between the coil temperature and the ambient
temperature.
D)
Senses the suction pressure.
Answer:
C
Explanation:
A)
B)
C)
D)
100)
100)
On an air-to-water heat pump, where does the heat come from to defrost the outdoor coil?
A)
Outdoor heat strips
B)
Indoor air
C)
Outdoor air
D)
Buffer tank
Answer:
D
Explanation:
A)
B)
C)
D)
27
101)
101)
What is the drawback of emergency heat?
A)
The supplemental heat costs more to operate than a heat pump.
B)
It activates the supplemental heat in the first stage.
C)
It causes problems with the refrigeration systems.
D)
The compressor and outdoor fan are not energized.
Answer:
A
Explanation:
A)
B)
C)
D)
102)
102)
What does the O thermostat terminal energize on most heat pumps?
A)
The indoor fan
B)
The compressor contactor
C)
The reversing valve
D)
The electric heat strips
Answer:
C
Explanation:
A)
B)
C)
D)
103)
103)
Why does an air-source heat pump system's heating capacity decrease as the outdoor temperature
decreases?
A)
The compression ratio decreases because the evaporator pressure increases.
B)
The compression ratio decreases because the evaporator pressure decreases.
C)
The compression ratio increases because the evaporator pressure decreases.
D)
The compression ratio increases because the evaporator pressure increases.
Answer:
C
Explanation:
A)
B)
C)
D)
104)
104)
Which of the following is a factor in deciding a unit's balance point?
A)
Temperature of the outside air
B)
Age of the heating system
C)
Size of the space being heated or cooled
D)
Amount of 5-kW electric strip heaters
Answer:
C
Explanation:
A)
B)
C)
D)
28
105)
105)
What does the outdoor air thermostat control?
A)
It prevents operation of the heat pump above its setpoint.
B)
It prevents operation of the electric heating elements above its setpoint.
C)
It controls the defrost cycle.
D)
It controls whether or not the heat pump operates in heating or cooling.
Answer:
B
Explanation:
A)
B)
C)
D)
106)
106)
What does the emergency heat setting do on a heat pump thermostat?
A)
Shuts down all system operation to prevent damage to the system components
B)
Sounds an alarm whenever the temperature drops below the thermostat set point
C)
Adds auxiliary heat to the heat from the refrigeration circuit in cold weather
D)
De-energizes the refrigeration circuit and operates the system on auxiliary heat
Answer:
D
Explanation:
A)
B)
C)
D)
107)
107)
What is the buffer tank on an air-to-water heat pump system?
A)
A large insulated tank of water that is heated with electric heating elements and serves as a
backup heat source
B)
A tank in the liquid line after the condenser that balances fluctuations in system capacity
C)
A large insulated tank of water that balances fluctuations in load
D)
A tank in the suction line before the compressor that prevents liquid from returning to the
compressor
Answer:
C
Explanation:
A)
B)
C)
D)
108)
108)
As the outside air temperature drops, the heating efficiency of air-to-air heat pumps:
A)
Remains the same.
B)
Increases.
C)
Decreases.
D)
Is unpredictable.
Answer:
C
Explanation:
A)
B)
C)
D)
29
109)
109)
Which terminal controls the reversing valve on most heat pumps?
A)
O/B terminal
B)
Y terminal
C)
G terminal
D)
W terminal
Answer:
A
Explanation:
A)
B)
C)
D)
110)
110)
The typical heat pump defrost termination temperature is around:
A)
50°F
B)
90°F
C)
28°F
D)
32°F
Answer:
A
Explanation:
A)
B)
C)
D)
111)
111)
How many mini-split heat pump systems would a house with four main rooms typically use?
A)
Mini-split systems cannot be used to condition buildings with more than one room.
B)
One mini-split system connected to ductwork to distribute the air
C)
One mini-split system in each room
D)
One mini-split system installed in a central location
Answer:
C
Explanation:
A)
B)
C)
D)
112)
112)
Which terminal controls second-stage heat on most heat pumps?
A)
W terminal
B)
O/B terminal
C)
G terminal
D)
Y terminal
Answer:
A
Explanation:
A)
B)
C)
D)
113)
113)
Which type of heat pump system can be used with a hot water radiant floor heating system?
A)
Traditional mini-split
B)
Air-to-water
C)
Water-to-air
D)
Air-to-air
Answer:
B
Explanation:
A)
B)
C)
D)
30
114)
114)
Which system is designed to evaluate how efficient the heating of a pump is?
A)
EER
B)
Energy Star
C)
HSPF
D)
SEER
Answer:
C
Explanation:
A)
B)
C)
D)
115)
115)
A closed-loop system is practical only when:
A)
The geology, hydrology, and land availability meet the requirements for system installation.
B)
There is an adequate supply of water, it is of good quality, and local codes and regulations
permit groundwater disposal.
C)
Loops are closed horizontally, because they are the most economical.
D)
Loops are closed vertically, because they take up significantly less space.
Answer:
A
Explanation:
A)
B)
C)
D)
116)
116)
A water-source system that gets its water from a well and does not reuse the water is:
A)
Considered a hybrid between an open- and a closed-loop system.
B)
A closed-loop system.
C)
An open-loop system.
D)
Called a quasi-closed loop because it still uses a circulating pump.
Answer:
C
Explanation:
A)
B)
C)
D)
117)
117)
What type of metering device do most packaged water source heat pumps use?
A)
Single bi-flow thermostatic expansion valve
B)
Single low-side float control
C)
Single capillary tube
D)
Single orifice style metering device
Answer:
A
Explanation:
A)
B)
C)
D)
31
118)
118)
There are no check valves or extra metering devices on most water-source packaged units
because:
A)
The heat exchangers are most often made of copper, cupronickel, or stainless steel.
B)
Most water-source packaged units use a single bi-flow thermostatic expansion valve.
C)
Most water-source packaged units use suction line accumulators and charge compensators.
D)
Water-source packaged units have a much lower operating temperature range than
air-source units.
Answer:
B
Explanation:
A)
B)
C)
D)
119)
119)
When is the air coil in a water-source heat pump the acting condenser?
A)
In the cooling cycle
B)
In the heating cycle
C)
On the defrost cycle
D)
Only when the unit is operating
Answer:
B
Explanation:
A)
B)
C)
D)
120)
120)
A water-source system that recirculates water in pipes buried in the ground is:
A)
Considered a hybrid between an open- and a closed-loop system.
B)
Called a quasi-open loop because it still must have an air gap at the circulating pump.
C)
A closed-loop system.
D)
An open-loop system.
Answer:
C
Explanation:
A)
B)
C)
D)
121)
121)
The temperature of the ground stays nearly constant at any depth below:
A)
The frost line.
B)
28 feet.
C)
4 feet.
D)
6 feet.
Answer:
B
Explanation:
A)
B)
C)
D)
32
122)
122)
When is the water coil in a water-source heat pump the acting evaporator?
A)
In the cooling cycle
B)
In the heating cycle
C)
In the defrost cycle
D)
Only when the unit is operating
Answer:
B
Explanation:
A)
B)
C)
D)
123)
123)
Most pond and lake water would not be suitable for an open-loop system because:
A)
Water in lakes and ponds has too low a specific gravity.
B)
It contains too many minerals and contaminants that would lead to scale buildup inside the
system.
C)
Locating the equipment in the pond would short out the electrical connections.
D)
Most ponds do not hold enough water.
Answer:
B
Explanation:
A)
B)
C)
D)
124)
124)
An open-loop system is practical only if:
A)
A local stream or pond can be used as the water supply.
B)
Local codes allow discharge of nontoxic antifreeze solutions into the water supply.
C)
There is an adequate supply of water and it is of good quality.
D)
The secondary refrigerant loop temperature can be closely monitored.
Answer:
C
Explanation:
A)
B)
C)
D)
125)
125)
Geothermal heat pumps get most of their heat from:
A)
The ground.
B)
The surrounding air.
C)
A separate gas-fired boiler.
D)
The electricity used to operate the compressor.
Answer:
A
Explanation:
A)
B)
C)
D)
33
126)
126)
When is the water coil in a water-source heat pump the acting condenser?
A)
In the cooling cycle
B)
In the heating cycle
C)
In the defrost cycle
D)
Only when the unit is operating
Answer:
A
Explanation:
A)
B)
C)
D)
127)
127)
The fluid circulated through the water coil of a geothermal heat pump system:
A)
Is circulated through a cooling tower.
B)
Is circulated through a heat transfer loop buried in the ground.
C)
Comes from condensation water collected off the evaporator.
D)
Is typically connected to the local water utility system.
Answer:
B
Explanation:
A)
B)
C)
D)
128)
128)
A water-source heat pump does not require a defrost cycle because:
A)
There are no check valves or extra metering devices within a water-source heat pump.
B)
The fluid circulating through the water-source unit cannot be allowed to freeze.
C)
It uses buried loops in which water is circulated, and the heat is then extracted from the
water.
D)
Most water-source units use a single bi-flow thermostatic expansion valve.
Answer:
B
Explanation:
A)
B)
C)
D)
129)
129)
What type of heat pump systems require a secondary refrigerant?
A)
Older CFC systems whose primary refrigerant is no longer available
B)
Closed-loop water-source systems
C)
Two-stage systems
D)
Cascade heat pump systems
Answer:
B
Explanation:
A)
B)
C)
D)
34
130)
130)
An example of an open-loop geothermal water-source heat pump application would be a system
connected to a:
A)
Lake loop.
B)
Well.
C)
Slinky loop.
D)
Vertical loop.
Answer:
B
Explanation:
A)
B)
C)
D)
131)
131)
How can many water-source heat pump systems be configured to supply hot domestic water?
A)
By adjusting the power of the condenser and heat pump
B)
By adjusting the load EWT and LWT levels to a higher temperature, which ensures enough
water for heating and domestic use
C)
By lengthening the evaporator coil and attaching it to an electric hot-water heater
D)
By using de-superheating coils and water-circulating pumps built into many systems
Answer:
D
Explanation:
A)
B)
C)
D)
132)
132)
Unlike other types of systems, geothermal systems do not lose capacity as the air temperature
drops because:
A)
They extract water from the ground, which is at a variable temperature.
B)
They extract air from the ground, which is at a stable temperature.
C)
They extract air from the ground, which is at a variable temperature.
D)
They extract heat from the ground, which is at a stable temperature.
Answer:
D
Explanation:
A)
B)
C)
D)
133)
133)
What type of defrost do geothermal systems use?
A)
They do not need defrosting.
B)
Adaptive defrost using the ground temperature
C)
Adaptive defrost using the air temperature
D)
Traditional time-temperature defrost
Answer:
A
Explanation:
A)
B)
C)
D)
35
134)
134)
What safety precaution should you follow when opening the split-system installation valves?
A)
Do not overtighten in the backseat direction.
B)
Make sure that they are frontseat cracked before operating the system.
C)
Always make sure they are securely backseated.
D)
Make sure they are securely frontseated before operating the system.
Answer:
A
Explanation:
A)
B)
C)
D)
135)
135)
In general, air-source heat pumps are sized to meet:
A)
The building heating load.
B)
Whichever is largest, the cooling load or the heating load.
C)
The building cooling load.
D)
The sum of the building heating and cooling load.
Answer:
C
Explanation:
A)
B)
C)
D)
136)
136)
How does heat capacity correlate with outdoor temperature on a balance point graph?
A)
As outdoor temperature increases, heat pump capacity decreases.
B)
As outdoor temperature increases, the balance point decreases.
C)
As outdoor temperature increases, heat pump capacity increases.
D)
As outdoor temperature increases, heat pump capacity remains constant.
Answer:
C
Explanation:
A)
B)
C)
D)
137)
137)
During the initial startup of a geothermal water-source heat pump, when should the water flow
be checked and adjusted?
A)
After operating the unit for at least 15 minutes
B)
After checking the system refrigerant pressures and amp draw
C)
First, before operating the system
D)
After making sure the refrigerant charge and airflow are correct
Answer:
C
Explanation:
A)
B)
C)
D)
36
138)
138)
Why should the water flow be checked before checking other system operating characteristics?
A)
A system operating with a low flow rate may require additional refrigerant.
B)
The system will not function at all with an incorrect flow rate.
C)
The flow rate affects the other system operating characteristics.
D)
A low flow rate introduces too much air into the system.
Answer:
C
Explanation:
A)
B)
C)
D)
139)
139)
Why is the drain for condensate water normally trapped?
A)
To funnel water to the auxiliary drain
B)
To trigger the condensate sump pump
C)
To reduce humidity
D)
To stop water from standing in the drain pan
Answer:
D
Explanation:
A)
B)
C)
D)
140)
140)
The primary and auxiliary drain lines should be:
A)
Piped together to ensure proper drainage.
B)
Piped separately.
C)
Run level to assure an air seal.
D)
Connected inside the unit and then piped out together.
Answer:
B
Explanation:
A)
B)
C)
D)
141)
141)
Where can a technician determine the correct water flow rate for a water-source system?
A)
Look on the data plate.
B)
Look at the manufacturer's specification sheet.
C)
Adjust the water flow until the compressor is operating at its RLA rating point.
D)
4 GPM × tons = water flow
Answer:
B
Explanation:
A)
B)
C)
D)
37
142)
142)
What information is necessary to determine a system balance point?
A)
The balance point is determined as part of the heat load study before the equipment is
chosen.
B)
The balance point for all AHRI rated heat pumps is 35°F.
C)
The manufacturer's installation instructions, which publish the equipment balance point
D)
A heat load calculation and the system capacity at two operating conditions
Answer:
D
Explanation:
A)
B)
C)
D)
143)
143)
When a geothermal heat pump system uses antifreeze in the loop, how is antifreeze added to the
loop?
A)
By temporarily connecting a purge unit
B)
By pouring the antifreeze in the loop before it is connected
C)
By pumping the antifreeze in under pressure
D)
By pouring the antifreeze in the loop after it is connected
Answer:
A
Explanation:
A)
B)
C)
D)
144)
144)
The auxiliary drain pan should be:
A)
Piped into the same drain line as the primary drain.
B)
1 inch larger than the primary drain dimensions.
C)
Located inside the unit under the primary drain.
D)
Larger than the overall unit dimensions.
Answer:
D
Explanation:
A)
B)
C)
D)
145)
145)
What is the additional charge required for a system with a factory charge of 56 oz of R-410A, an
assumed length of 15 ft, and a3/8 in liquid line that is 35 ft long?
A)
56 oz + 21 oz = 77 oz
B)
56 oz + 12 oz = 68 oz
C)
35 × 0.6 = 21 oz
D)
(35 - 15) × 0.6 = 12 oz
Answer:
D
Explanation:
A)
B)
C)
D)
38
146)
146)
Air-source packaged heat pumps are commonly available in:
A)
Side discharge, bottom discharge, or wall mount configurations.
B)
Gas-fired, oil-fired, and electric units.
C)
Top discharge, bottom discharge, and floor mount configurations.
Answer:
A
Explanation:
A)
B)
C)
147)
147)
After leaving the unit, condensate drain lines should be run:
A)
Level for a neat appearance.
B)
With a minimum fall of at least 1/8 inch per foot.
C)
With a maximum rise of 1/8 inch per foot.
D)
To the nearest plumbing waste vent.
Answer:
B
Explanation:
A)
B)
C)
D)
148)
148)
How can air be removed from a newly installed ground loop?
A)
By temporarily connecting the purge unit
B)
By adding low-toxicity antifreeze to the system
C)
By purging the loop with nitrogen before connecting it to the system
D)
By running water through the loop after connecting it to the system
Answer:
A
Explanation:
A)
B)
C)
D)
149)
149)
What is the purpose of shutoff valves in the water loop of a water-source heat pump?
A)
They allow you to service a water-source unit.
B)
They allow water pressure to build.
C)
They are used to shut off different loop zones in a zoned loop system.
D)
They keep water inside the piping system.
Answer:
A
Explanation:
A)
B)
C)
D)
39
150)
150)
How can you dispose of water on top of the ground if it cannot enter the groundwater?
A)
By draining the water to a lake off the property
B)
By redirecting the water to a holding pond
C)
By redirecting the water into a well
D)
By altering the pH level of the water
Answer:
B
Explanation:
A)
B)
C)
D)
151)
151)
Why would you use supply registers with curved louvers?
A)
The system has higher airflow.
B)
The air disperses throughout the room.
C)
The system operates more efficiently.
D)
The occupants feel less of a draft.
Answer:
D
Explanation:
A)
B)
C)
D)
152)
152)
How does a pressure-time-temperature defrost system measure frost?
A)
The system has a timer control triggered by pressure drop.
B)
The system has a timing circuit that controls the defrost thermostat.
C)
The system has a reversing valve that controls the defrost thermostat.
D)
The system has a differential airflow pressure switch.
Answer:
D
Explanation:
A)
B)
C)
D)
153)
153)
Which of the following signifies a power supply issue?
A)
A temperature drop
B)
Inconsistent airflow
C)
A malfunctioning thermostat
D)
Inconsistent water flow
Answer:
C
Explanation:
A)
B)
C)
D)
40
